As the diameter of blood vessels varies from individual to individual, as well as within the individual, it is desirable to have a vascular graft prosthesis tube which has a diameter on one end larger than the other, and preferably has an axially tapered or stepped diameter The varying diameter of the tube provides the surgeon with a variety of different diameters of prosthesis from which to match to the size of the blood vessel being replaced
One of the common applications for vascular graft prostheses is in an arterial-venous fistula or shunt from an artery to a vein for patients who require hemodialysis. When the arterial-venous fistula is in place, the capillaries which ordinarily serve as the transition from the artery to the vein are bypassed. The radial artery, which transports blood to the hands, is typically used in the arterial-venous fistula procedure.
One of the difficulties encountered during the arterial-venous fistula procedure is the "steal" syndrome, whereby too much blood flows through the fistula or shunt and insufficient amounts of blood arrive at the extremity, e.g., the hands. Utilizing a vascular graft prosthesis which is longitudinally tapered providing a smaller diameter at one end gradually increasing to a larger diameter at the other end, decreases the amount of blood flowing through the vascular graft prosthesis and thereby increases the blood flow to the extremity.
In view of the foregoing, a method for providing a tapered vascular graft prosthesis is desired In some situations it may also be desirable to provide tubing which has a thinner wall.